1. Field of the Invention
The present invention relates to an image-taking apparatus that includes an imaging device and generates image data representing a subject image formed on the imaging device in response to a shooting operation.
2. Description of the Related Art
A digital camera is a typical example of image-taking apparatus. Conventional digital cameras have an exposure control system, which is a technique for determining exposure, such as average metering, multi-zone metering, center-weighted metering and spot metering. Any of these employed in a digital camera as an exposure control system depends on the type of the digital camera.
The average metering is a system that obtains an average intensity by metering the entire shooting area and determines an exposure based on the result of metering. The multi-zone metering is a system that divides a shooting area into multiple metered areas and determines an exposure based on the result of measuring the metered areas. The center-weighted metering is a system that meters a central portion (30% to 40%) of a shooting area and determines the exposure based on the result of measuring the central portion. The spot metering is a system that meters a center (several percent) of a shooting area and determines the exposure based on the result of measuring the center.
However, these systems may not be suitable for shooting of an image including a person, because an exposure value obtained by these systems is not always appropriate for the face of a person in the image.
Japanese Patent Application Publication No. 2003-10755 proposes a technique for shooting an image with an exposure value suitable for the face of a person in the image. In this technique, the face of a person in an image is detected, and metering is respectively performed on the detected face and a shooting area corresponding to the entire screen. Based on the metering results, an exposure value centered on the face portion is determined so that an image can be taken with a correct exposure for the face.
Meanwhile, Japanese Patent Application Publication No. 2005-86682 discloses a technique for metering one selected from two or more faces when the faces are detected, and shooting an image with a correct exposure for the selected face based on the result of the metering.
According to the technique disclosed in Japanese Patent Application Publication No. 2003-10755, it is possible to shoot an image including only one person with a correct exposure for the face of the person.
However, the technique disclosed in Japanese Patent Application Publication No. 2003-10755 has such a drawback that it is incapable of obtaining an exposure value centered on two or more faces of different intensity levels when the faces are detected, resulting in a shooting with an exposure value unsuitable for some faces.
Also, the technique disclosed in Japanese Patent Application Publication No. 2005-86682 has such a problem that because the exposure is made suitable for the selected one of the two or more faces, an image is taken with the exposure suitable only for the selected face but unsuitable for other faces.